Laser-induced breakdown spectroscopy detection and classification of biological aerosols.
TL;DR: In this paper, a spectrally broadband laser-induced breakdown spectroscopy (LIBS) system was used for laboratory measurements on some common biological agent simulants, which were compared to those of common, naturally occurring biological aerosol components (pollen and fungal spores) to determine the potential of LIBS for discriminating biological agents from natural background aerosols.
Abstract: Laser-induced breakdown spectroscopy (LIBS) is examined as a potential method for detecting airborne biological agents. A spectrally broadband LIBS system was used for laboratory measurements on some common biological agent simulants. These measurements were compared to those of common, naturally occurring biological aerosol components (pollen and fungal spores) to determine the potential of LIBS for discriminating biological agents from natural background aerosols. A principal components analysis illustrates that linear combinations of the detected atomic lines, which are present in different ratios in each of the samples tested, can be used to discriminate biological agent simulants from other biological matter. A more sensitive, narrowband LIBS instrument was used to demonstrate the detection of single simulant (Bg) particles in the size range 1-5 μm. Ca, Mg, and Na, which are present in varying concentrations between 0.3 and 11% (by mass) in the Bg particles, were observed in single particles using LIBS.
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TL;DR: The current state-of-the-art of analytical LIBS is summarized, providing a contemporary snapshot of LIBS applications, and highlighting new directions in laser-induced breakdown spectroscopy, such as novel approaches, instrumental developments, and advanced use of chemometric tools are discussed.
Abstract: The first part of this two-part review focused on the fundamental and diagnostics aspects of laser-induced plasmas, only touching briefly upon concepts such as sensitivity and detection limits and largely omitting any discussion of the vast panorama of the practical applications of the technique. Clearly a true LIBS community has emerged, which promises to quicken the pace of LIBS developments, applications, and implementations. With this second part, a more applied flavor is taken, and its intended goal is summarizing the current state-of-the-art of analytical LIBS, providing a contemporary snapshot of LIBS applications, and highlighting new directions in laser-induced breakdown spectroscopy, such as novel approaches, instrumental developments, and advanced use of chemometric tools. More specifically, we discuss instrumental and analytical approaches (e.g., double- and multi-pulse LIBS to improve the sensitivity), calibration-free approaches, hyphenated approaches in which techniques such as Raman and fluorescence are coupled with LIBS to increase sensitivity and information power, resonantly enhanced LIBS approaches, signal processing and optimization (e.g., signal-to-noise analysis), and finally applications. An attempt is made to provide an updated view of the role played by LIBS in the various fields, with emphasis on applications considered to be unique. We finally try to assess where LIBS is going as an analytical field, where in our opinion it should go, and what should still be done for consolidating the technique as a mature method of chemical analysis.
1,159 citations
TL;DR: A review of the current knowledge on major categories of primary biological aerosol particles (PBAP): bacteria and archaea, fungal spores and fragments, pollen, viruses, algae and cyanobacteria, biological crusts and lichens and others like plant or animal fragments and detritus is presented in this article.
Abstract: Atmospheric aerosol particles of biological origin are a very diverse group of biological materials and structures, including microorganisms, dispersal units, fragments and excretions of biological organisms. In recent years, the impact of biological aerosol particles on atmospheric processes has been studied with increasing intensity, and a wealth of new information and insights has been gained. This review outlines the current knowledge on major categories of primary biological aerosol particles (PBAP): bacteria and archaea, fungal spores and fragments, pollen, viruses, algae and cyanobacteria, biological crusts and lichens and others like plant or animal fragments and detritus. We give an overview of sampling methods and physical, chemical and biological techniques for PBAP analysis (cultivation, microscopy, DNA/RNA analysis, chemical tracers, optical and mass spectrometry, etc.). Moreover, we address and summarise the current understanding and open questions concerning the influence of PBAP on the atmosphere and climate, i.e. their optical properties and their ability to act as ice nuclei (IN) or cloud condensation nuclei (CCN). We suggest that the following research activities should be pursued in future studies of atmospheric biological aerosol particles: (1) develop efficient and reliable analytical techniques for the identification and quantification of PBAP; (2) apply advanced and standardised techniques to determine the abundance and diversity of PBAP and their seasonal variation at regional and global scales (atmospheric biogeography); (3) determine the emission rates, optical properties, IN and CCN activity of PBAP in field measurements and laboratory experiments; (4) use field and laboratory data to constrain numerical models of atmospheric transport, transformation and climate effects of PBAP. Keywords: primary biological atmospheric aerosol; climate; cloud condensation nuclei; biology; atmospheric ice nuclei (Published: 22 February 2012) Citation: Tellus B 2012, 64 , 15598, DOI: 10.3402/tellusb.v64i0.15598
1,034 citations
TL;DR: In this paper, the chemical properties of particulate matter (PM) in diesel vehicle exhaust at a time when emission regulations, diesel technology development, and particle characterization techniques are all undergoing rapid change are examined.
820 citations
TL;DR: In this paper, the authors used a single-pulse laser source over a doublepulse system as the most suitable source for the stand-off analysis of organic samples for the detection and characterization of energetic materials at distances up to 45 m using standoff laser induced breakdown spectroscopy (LIBS).
Abstract: The detection and characterization of energetic materials at distances up to 45 m using stand-off laser induced breakdown spectroscopy (LIBS) has been demonstrated. A field-portable open-path LIB spectrometer working under a coaxial configuration was used. A preliminary study allowed choosing a single-pulse laser source over a double-pulse system as the most suitable source for the stand-off analysis of organic samples. The C2 Swan system, as well as the hydrogen, oxygen and nitrogen emission intensity ratios were the necessary parameters to identify the analyte as an organic explosive, organic non-explosive and non-organic samples. O/N intensity ratios of 2.9 and 2.16 with relative standard deviations of 4.03% and 8.36% were obtained for 2,4-dinitrotoluene and aluminium samples, respectively. A field test with known samples and a blind test were carried out at a distance of 30 m from the sample. Identification of energetic compounds in such conditions resulted in 19 correct results out of 21 samples.
240 citations
TL;DR: In this paper, the authors present an overview of the laser-induced breakdown spectroscopy (LIBS) method, discussing its many advantages and some important limitations as an analytical method and how these relate to potential applications.
Abstract: During the past decade there has been intense activity in the field of laser-induced breakdown spectroscopy (LIBS). This activity includes studies of laser ablation and properties of the laser spark, the development of methods to enhance LIBS detection capabilities, and the application of LIBS to specific analysis needs. The unique capabilities of LIBS make it particularly suited for applications that cannot be addressed by conventional analytical methods. Potential applications of the method are numerous and several applications have been realized, resulting in on-line operating instruments. Other applications will require that the method be developed further to improve analytical performance. Here we present an overview of the LIBS method, discussing its many advantages and some important limitations as an analytical method and how these relate to potential applications.
188 citations
References
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06 Jul 1993
TL;DR: In this article, Jaenicke et al. discuss the effects of clouds on Earth's climate and large scale models of clouds in large-scale 3D models. But they do not discuss the relationship between clouds and climate.
Abstract: R Jaenicke, Tropospheric Aerosol P V Hobbs, Aerosol-Cloud Interactions Dr Harshvardhan, Aerosol-Climate Interactions A Heymsfield, Structures of Clouds M King, Radiative Properties of Clouds DL Hartmann, Radiative Effects of Clouds on Earth's Climate H Sundquist, Parameterizafion of Clouds in Large-Scale Models MP McCormick, Stratospheric Aerosol and Clouds Subject index
276 citations
TL;DR: In this article, a high-powered laser beam is focused onto a small area or spot of a solid surface, the temperature of the locally heated region rises rapidly to the vaporization temperature of solid material and an optically induced plasma, frequently called a laser-induced plasma (LIP) or laser-ablated plasma or laser spark is formed at the surface.
Abstract: INTRODUCTION When a high-powered laser beam is focused onto a small area or spot of a solid surface, the temperature of the locally heated region rises rapidly to the vaporization temperature of the solid material and an optically induced plasma, frequently called a laser-induced plasma (LIP) or laser-ablated plasma (LAP) or laser spark is formed at the surface. The plasma will be formed when the laser power density exceeds the breakdown threshold value of the solid surface. Although different materials have different breakdown thresholds, an optical plasma is produced when the laser power density exceeds several megawatts per centimeter squared (106 - 109 W/cm2). This plasma has been used for sampling, atomization, excitation, and ionization in analyhcal atomic spectroscopy. It has also been frequently used and proposed as a source for atomic emission spectrometry (AES). In this case the technique is most ofien referred to as laser microprobe optical emission spectrometry (LM-OES) developed by Brech and ...
264 citations
TL;DR: Initial tests with nebulised Bacillus subtilis var.
240 citations
TL;DR: In this paper, the size distributions of monodisperse particle source flows were measured using the laser-induced breakdown spectroscopy (LIBS) technique for calcium- and magnesium-based aerosols.
Abstract: Laser-induced breakdown spectroscopy (LIBS) was evaluated as a means for quantitative analysis of the size, mass, and composition of individual micron-to submicron-sized aerosol particles over a range of well-characterized experimental conditions. Conditional data analysis was used to identify LIBS spectra that correspond to discrete aerosol particles under low aerosol particle loadings. The size distributions of monodisperse particle source flows were measured using the LIBS technique for calcium- and magnesium-based aerosols. The resulting size distributions were in good agreement with independently measured size distribution data. A lower size detection limit of 175 nm was determined for the calcium- and magnesium-based particles, which corresponds to a detectable mass of approximately 3 femtograms. In addition, the accuracy of the LIBS technique for the interference-free analysis of different particle types was verified using a binary aerosol system of calcium-based and chromium particles.
202 citations